Loads can be lifted and stacked and unstacked to very great heights by means of a reach-type forklift truck. So that the operator can rapidly and safely stack a pallet in a rack or unstack it therefrom, it is known to associate a video camera with the tines of the forklift. The driver can identify on the screen in the cab whether the height, the lateral position or the inclination of the forklift has to be altered.
With such vehicles, it is furthermore known to pre-select the fork elevation height. When the operator knows from the outset the height to which the load has to be lifted, said height can be entered as a pre-selected fork elevation height and the fork elevation height measured by a fork elevation height measuring device is compared with the pre-set height in a control device. In this manner, the forklift can be automatically moved into the desired position before the definitive stacking or unstacking. In this connection, it has furthermore been known to make the fork elevation height pre-selection menu visible on a visualisation means. Finally, it is known to provide both a fork elevation height pre-selection menu and a video menu. A disadvantage therewith is that the view of the operator continually has to be refocused, depending on which visualisation means is watched, as both are activated during operation.
A total of six different operating modes are disclosed in EP 1 408 001 A1 for a stacking aid or automatic stacking for an industrial truck. Display means are provided to display the position of a load carrying means on, for example, a screen, the position being detected by an appropriate detector. A further detector can, for example, determine whether a load is present on the load carrying means. Automatic stacking can take place in a specific operating mode. Furthermore, in a further mode, the position of the load carrying means can be detected, in order, for example, to effect automatic lifting or lowering, in order to pick up a load.
The object of the invention is to produce a device for aiding stacking and unstacking for a stacker truck which is reduced in cost relative to known devices and is simpler to handle.